Programming

Regenerating an Error

Use the rethrow function to regenerate an error that has previously been thrown. You may want to do this from the catch part of a try-catch block, for example, after performing some required cleanup tasks following an error.

This is how you would rethrow an error in a try-catch block:

• try
     do_something
  catch
     do_cleanup
     rethrow(lasterror)
  end
  

rethrow generates an error based on the err input argument that you provide. This argument must be a MATLAB structure with at least the following two fields.

Field Name	Description
message	Text of the error message
identifier	Message identifier of the error message

If you simply want to regenerate the last error that occurred, the lasterror function returns a structure that can then be passed directly to rethrow.

Note    lasterror is not the same as lasterr. The lasterror function returns a structure array that contains the message string and message identifier for the last error, and may contain more information in future versions of MATLAB. The lasterr function returns one or two character arrays that contain only the message string and identifier.

Identifying the Cause

Message Identifiers

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